据密码长度 显示安全条

//根据密码长度显示安全条

<ul class="clear">
    <li>密　　码：</li>
    <li> <input type="password" id="pwd" name="pwd" class="in" onKeyUp=pwStrength(this.value) onBlur=pw_y("pwd","pwd1")></li>
    <li><em class="red">*</em></li>
    <li class="i2 grey"><table border="0" bordercolor="#cccccc" style='display:marker'>
        <tr align="center">
            <td  id="strength_L"  bgcolor="#eeeeee">弱</td>
            <td  id="strength_M" bgcolor="#eeeeee">中</td>
            <td id="strength_H" bgcolor="#eeeeee">强</td>
            <td align="left" >
                <label id="pwd1">使用数字，字母，下划线，长度在 6 - 20 个字符之间</label></td>
        </tr>
    </table>
    </li>
</ul>

function pwStrength(pwd){
O_color="#eeeeee";
L_color="#FF0000";
M_color="#FF9900";
H_color="#33CC00";
if (pwd==null||pwd==''){
Lcolor=Mcolor=Hcolor=O_color;
}else{
S_level=checkStrong(pwd);
switch(S_level) {
case 0:
Lcolor=Mcolor=Hcolor=O_color;
case 1:
Lcolor=L_color;
Mcolor=Hcolor=O_color;
break;
case 2:
Lcolor=Mcolor=M_color;
Hcolor=O_color;
break;
default:
Lcolor=Mcolor=Hcolor=H_color;
}
}
document.getElementById("strength_L").style.background=Lcolor;
document.getElementById("strength_M").style.background=Mcolor;
document.getElementById("strength_H").style.background=Hcolor;
return;
}